Practice: Permit-Required Confined Spaces in Construction

A 6-foot deep manhole with electrical splice work is best classified as which type of space?

• A permit-required confined space

• An excavation, not a confined space

• A controlling contractor work area

• A non-permit confined space

Answer explanation

Limited entry, no continuous occupancy design, and recognized electrical hazards combine to make this a permit-required confined space. A non-permit space has no serious hazards.

Tags

Blooms Level: Apply

Atmospheric testing inside a permit space should occur in what order?

• Oxygen, flammability, toxicity

• Oxygen, toxicity, flammability

• Flammability, oxygen, toxicity

• Toxicity, oxygen, flammability

Answer explanation

Oxygen is tested first because most combustible gas meters need adequate oxygen to read accurately. Flammability comes next, then toxic gases.

Tags

Blooms Level: Apply

An attendant sees an entrant collapse inside a tank. What should the attendant do first?

• Call rescue services and stay outside

• Close the permit and ventilate the space

• Begin atmospheric retesting from outside

• Enter the tank to pull the worker out

Answer explanation

Attendants must never enter to perform rescue. They summon trained rescuers and remain at the entry point to monitor and communicate.

Tags

Blooms Level: Apply

Which oxygen reading inside a confined space requires immediate evacuation?

• 20.5%

• 19.0%

• 21.0%

• 20.9%

Answer explanation

Oxygen below 19.5% is oxygen-deficient and immediately dangerous. Normal air is 20.9%, and readings at or above 19.5% are within the acceptable range.

Tags

Blooms Level: Apply

Which document authorizes workers to enter a permit-required confined space?

• The lockout tagout log

• The site safety plan

• The entry permit

• The job hazard analysis

Answer explanation

The entry permit lists hazards, controls, testing results, and authorized personnel, and must be posted and signed before entry begins. A job hazard analysis identifies risks but does not authorize entry.

Tags

Blooms Level: Remember

A welder performs hot work inside a steel vessel. What is the greatest atmospheric concern?

• Engulfment by welding slag buildup

• Loss of radio communication signal

• Reduced visibility from arc flash

• Oxygen enrichment from leaking cylinders

Answer explanation

Leaking oxygen or fuel-gas hoses enrich the atmosphere and dramatically increase fire and explosion risk. Cylinders must never be brought inside a confined space.

Tags

Blooms Level: Apply

Which task is the entry supervisor responsible for during the job?

• Logging tools brought into the space

• Testing the air continuously from inside

• Performing rescue if an entrant collapses

• Terminating entry when conditions change

Answer explanation

The entry supervisor authorizes, oversees, and terminates entry when conditions are unsafe or work is complete. Continuous testing is typically the attendant's role.

Tags

Blooms Level: Understand

How should an unidentified, unevaluated sump below a floor grate be treated?

• A non-permit space until tested

• An excavation under applicable trenching rules

• A permit-required space until evaluated otherwise

• A confined space exempt from atmospheric testing

Answer explanation

Unknown spaces are presumed permit-required until a competent person evaluates and reclassifies them. This default protects workers from unrecognized hazards.

Tags

Blooms Level: Apply

Why is continuous atmospheric monitoring required during confined space entry?

• Permits expire every 30 minutes by rule

• Conditions inside a space can change rapidly

• Single readings cannot detect oxygen levels

• Attendants cannot observe entrants without it

Answer explanation

Ventilation failures, hot work, or shifting materials can alter the atmosphere quickly. Continuous monitoring detects dangerous changes before entrants are harmed.

Tags

Blooms Level: Understand

Which is a physical, not atmospheric, hazard inside a confined space?

• Moving auger or mixer blades

• Carbon monoxide from engines

• Methane from decomposing waste

• Hydrogen sulfide buildup

Answer explanation

Mechanical hazards like augers and mixers are physical hazards. Carbon monoxide, methane, and hydrogen sulfide are all atmospheric hazards.

Tags

Blooms Level: Remember